Java–;MySQL连接获取程序
我需要将我的连接发送到CarDAO类。我为此创建了getMyConn getter,但它键入“myConn无法解析为变量”。我怎样才能为它创建getter呢Java–;MySQL连接获取程序,java,mysql,database-connection,getter,Java,Mysql,Database Connection,Getter,我需要将我的连接发送到CarDAO类。我为此创建了getMyConn getter,但它键入“myConn无法解析为变量”。我怎样才能为它创建getter呢 public class ConnectionDB { public ConnectionDB() { String dbHost="localhost"; String dbDatabase="cars"; String dbUser = "root"; Strin
public class ConnectionDB {
public ConnectionDB() {
String dbHost="localhost";
String dbDatabase="cars";
String dbUser = "root";
String dbPassword = "";
String connectionUrl = "jdbc:mysql://" + dbHost
+ "/" + dbDatabase
+ "?user=" + dbUser
+ "&password=" + dbPassword;
try{
// 1. Get a connection do database
Connection myConn = DriverManager.getConnection(connectionUrl);
// 2. Create a statement
Statement myStmt = myConn.createStatement();
// 3. Execute SQL query
String sql = "";
//int rowsAffected = myStmt.executeUpdate(sql);
//System.out.println("Rows affected " + rowsAffected);
// 4. Process the result set
}
catch(Exception exc) {
exc.printStackTrace();
}
}
public Connection getMyConn(){
return myConn;
}
}
只需将myConn置于构造函数外部,使其成为对象的属性
Connection myConn;
然后,在构造函数中
try{
// 1. Get a connection do database
myConn = DriverManager.getConnection(connectionUrl);
// 2. Create a statement
Statement myStmt = myConn.createStatement();
// 3. Execute SQL query
String sql = "";
//int rowsAffected = myStmt.executeUpdate(sql);
//System.out.println("Rows affected " + rowsAffected);
// 4. Process the result set
}
此外,不建议在构造函数中初始化连接。您可以在需要时使用单例类来获取连接。在哪一行获得此错误?